A question of importance to the future direction of the biology of aging is whether the aging of independently aging components or subsystems of organisms has been synchronized by natural selection. The importance of the question derives from its connection with the very practical question whether it is possible, in a technical sense, to extend the natural lifespans of organisms via medical or prosthetic intervention: such a goal, which appears to have motivated a sizable segment of gerontological research, will only be practicable if aging is to a high degree unsynchronized. Despite its significance, however, no substantive work on the question has been accomplished. Presumably, this is due in part to the absence of analytical techniques for observing the hypothesized phenomenon, namely, synchronism of aging, in natural organisms and to the impracticability of the very large time scales of meaningful experiments. The key to the present propsal is the development of a discrete-event simulation model, based on well-established principles of reliability theory, that allows the phenomenon to be studied experimentally. A number of experiments are propsed that will generate basic knowledge about synchronism in complex systems. These include analysis of the effect of system type, the effect of natural selection pressure, the effect of extra-selective forces in evolution, and the possible long-term or global equilibrium of sychronism. By establishing a body of knowledge concerning synchronism in general systems, it should be possible to draw inferences as to the importance of the effect in the special case of living systems. An ultimate aim of the research is thereby to provide a theoretical basis for assessing, in connection with other information, whether extension of the human lifespan is technically feasible.